Four Germans have been charged with forming a terrorist group meant to target refugees. The Oldschool Society allegedly planned to bomb a shelter for asylum seekers.

Federal prosecutors in Germany announced on Wednesday that they had charged three men and one woman with forming a far-right terror group. Known as the Oldschool Society, the group was allegedly planning to detonate nail bombs at a home for asylum seekers.

The four suspects, who ranged in age from 23 to 57, are accused of meeting first in November 2014 with a larger group to discuss the “the manufacturing of explosives as well as attacks on Salafists and asylum seekers,” according to a prosecutors’ statement. By May 2015, when the four suspects were arrested, they already made a concrete plot “for a bomb attack at an inhabited refugee shelter.”

“They discussed wrapping the explosives with nails or fuel. But the attacks did not take place as they were arrested on May 6, 2015, and have since been in detention,” said authorities.